Posts Tagged ‘Test’

Wind is very often the recordist´s enemy. Especially if the rumbling noise of „hammering membrane“ is not acceptable.
Some recordists may say this rumbling noise is just normal. Everyone will hear similar rumbling noise when they stay in wind.
For me it sounds like „clipping distortion“.
Wind protection is one of the most important thing for nature recordings, especially in the country where wind below 3m/sec. is almost unique.
I have tried several wind protections. My own, Rode Blimp and Rycote Softie and Modular series. All of them sounds similar. So it was welcomed when Rycote introduced the Cyclone windshield. Cyclone have Floating Basket Suspension, which is very nice. Until now, it has been only be used in the overpriced Cinela products.
Rode NT1a is one of the best cardioid microphones available today for nature recording. But sadly it is not build for outdoor use, so it has some poor futures like handling noise.
So when I choose it on the field, it has been important to keep it in Rycote modular windshield, place it close to the ground (sadly very often too close) and pray for completely calm weather. Then pray again for nice outcome.
I per-order a pair of Cyclone mini windshield last summer and got it in mid September. My plan was to fix them with parallel MKH20/40. But I also gave my modified NT1a a try when I saw it was almost „plug and play“ to fix it .
Without fur Cyclone was not far from to be equal to Rycote modular series with fur. But when Cyclone was dressed in fur the rumbling noise almost disappeared in wind around 5-7 m/s. That was a huge success.
Following recording is a short part of overnight recording from Stafholtstungur, in the west of Iceland. The gust goes up to ca. 7m/sec. and the recorder HPF was set at 80Hz. The rig is about 1 meter above the ground.
Some rumble noise is audible in this recording, but some of it could as well be a vibration from the tripod. Keep it in mind this is NT1a which is particularly sensitive for handling noise.
I will spend more time to test this setup but it looks like I need to order another pair for my MKH20/40 rig.
Quality open headphones are recommended while listening at low to mid level.

When I use boom in recording I have used Audio Technica BP4025 stereo mic in Rycote windshield. It is not too heavy and it gives me stereo recordings. But very often I have been disappointed with the „musical“ sound quality, so I don´t often get quality ambiance recordings with this setup. Saying that, it does not mean BP4025 is a bad mic. BP4025 has a very low noise floor. It is the perfect mic for special circumstances like where size does matter and for very quiet environment/nature recordings.
DPA4060 is a pretty sounding miniature mic, sold in pairs and much lighter than any original stereo mic on the market. That means it is perfect to use for boom recordings. But because DPA4060 is an omni mic it is necessary to separate the capsules to get stereo. It is done in two ways. Separate the capsules with space (around 40cm) to get time difference, or place them in two sides of some sonic baffle materials.
The BP4025 was in a short Rycote WS2 windshield which has overall length (wide) 34cm. So it was important to place the capsules each side of some baffle material to get acceptable wide stereo.
I end up with a simple „binaural“ project I made out of wooden leftover (see pictures).
I decided not to use silicon artificial human ears because the ears will change the frequency curve at 2,5Khz and 5,5Khz, which means I needed to fix the EQ afterwards on all recordings made with this rig.
The result was stunning. The rig I made was lighter and better wight balanced than previous BP4025 setup. The overall wight is only 750gr (mics+wood baffle+WS2 basked+fur). It also gives me wider „stereo image“. But best of all, it withstands wind- and handling noise much better than previous BP4025 setup.
Following recordings are 4 and were made in three locations. The two first one are waves on seashore, then one from a cliff, 300 m above sea level with seabirds and the last one is from a football game in Reykjavik. All where recorded on Sound devices 744.
All recordings are straight from the recorder. Just cut and paste, fade in and out and then down grade from WAV to mp3.

The two first recordings are big and then small waves. The mic have fur, HPF is off and gain at 45db. The mics are faced from the beach to the fjords. You will hear car pass by „behind“ the mic. Notice, you will hear a short „drop out“ when it pass. It is because it passes my car which was located on the road side. See location.
In the cliff recording the mic is without fur. It is possible to hear how strong gust sounds on the Rycote basket, but that is anyway much better (or different) than the my previous BP4025 setup. HPF at 40Hz and gain at 45dB. The boom with the mic reaches the cliff edge about one meter. See location.
The last recording is from a football game celebration in downtown Reykjavik. No fur, HPF at 40Hz and gain at 40dB. The mic stood on a boom about 1 meter above the crowds head. See location.

This recordings include a spoken word from pocket radio at very low volume and ticking alarm clock in 1,6m distance. The volume settings on the radio was so low, the sound was hardly audible with bare ears. Noise from radiator pipeline is audible in the background. Miscellaneous bird life is outside and should be also clearly audible.
Keep in mind. This test is only noise and sensitivity comparison. High sensitivity and low noise is VERY important for nature recordings. This comparison does not give any information how this microphones sounds for music recording or how they withstand high pressure sound level.See spectrogram and pictures
Quality headphones recommended while listen.

Shure VP88, Rode NT4 and Audio Technica BP4025 direct from recorder. All at same gain level at 55dB.

All three recordings are now independently level normalized up to 0dB.

Some months ago my plan was to buy Rode NTG3. I was looking for a low noise and better sounding microphone than ME66 I already own. But after some research at home I found this microphone even worse than ME66 for nature recording.
The audible noise and sensitivity between these two mics was almost equal, but NTG3 have noticeably higher low frequency response.
But what surprised me most was all the noise in NTG3. If something, it was even more than in ME66. But spectrogram shows a shocking pictures for NTG3, a white noise in the whole frequency spectrum up to 50Khz. See spectrogram.
This NTG3 was sent back to the shop, but I was never sure if I did some mistakes in this measurements. So last week I vent to the shop and picked up some recording samples on the same NTG3.
The recorder was Sound devises 744 at 24bit/48Khz. NTG3 was in channel 1 and for comparison ME66 was in channel 2. They were laying side by side and the gain was in full position. Input filter for both channels was at 80Hz, 12dB/oct.
It is no doubt. There is some strange white noise in NTG3.
The sound sample below is about two minutes long. First minute is NTG3 and the second is ME66.
This particular NTG3 can be defective, so I am waiting for next supply of Rode NTG3 in the shop.
I will update this post as soon after I have got a chance to test some other NTG3 mics.See more pictures and spectrogram in this last test.

Conclusion – Summary

The spectrogram looks very bad for NTG3 but the mic is not as bad as it looks. The ME66 datasheets display referred noise as 10dB(A) and the NTG3 datasheets display referred noise as 13dB(A), so ME66 has lower referred noise than NTG3. This difference is probably what we see on the spectrogram. This microphones does not have exactly same bandwidth, as the ME66 has a reduced audio bandwidth which in turn reduces the referred noise. The ME66 top end roll off starts around 14Khz (0dB) and is -6dB at 20KHz, NTG3 is +2dB at 14KHz and -2dB at 20KHz.
NTG3 is RF biased microphones designed to withstand high humidity and harsher environments than the ME66 condenser microphone. So while the NTG3 and ME66 are both shotgun microphones they are designed for different operating conditions.
NTG3 would be my choice for most “normal sound pressure” level. But for quiet nature sounds where most audible sounds are in low level and mid-high frequency, I would choose some other mic.
In my opinion Rode NT1a is one of the best. Sadly NT1a is not a shotgun or small diaphragm condenser that can be fit nicely in a Blimp. But NT1a have only 5dB(A) noise and that makes the whole different for those who don’t like to use noise reduction software. See solutions how to fit NT1a in Blimp in NOS and XY setup.
For those who are searching for sound quality in NTG3 I recommend this search: http://www.google.com/search?hl=en&q=NTG3+vs+ME66&meta=
Also this one:http://www.google.co.uk/search?hl=en&q=NTG3+vs+MKH416&meta=

Rode NT4 and Shure VP88 was placed in the same place. Connected to Sound device 305 preamp. All filters at zero and gain and faders at 100%.
You shold hear the radio at low level (3 meters away), clock on a wall (2 meters) and a refrigerator (3 meters)
This is not a perfect test, but will give some information about noise and sensitivity between this two mics.